The problem of exploitation of cultivated land with the least expenditure of irrigation water, fertilizers, conditioners and the like is at the present time one of the most important both because of the scarcity of water, fertilizers and conditioners and because of the need to make agricultural land more productive.
Many systems have been developed for irrigation by means of spraying and drip, which waste large quantities of water, fertilizers, conditioners and the like due to absorption, evaporation, and loss to the wind during the distribution process which is effected on the surface, causing excessive surface wetting which favors the appearance and growth of parasite plants, and infestations of insects and fungus diseases, and which when carried out with large volumes of water may also produce erosion of the land under cultivation.
Furthermore, these traditional systems of irrigation require the use of hand labor for levelling the ground, and hence topographically irregular ground presents serious problems in bringing it under exploitation.
Furthermore, in those irrigation systems in which the water, fertilizers and conditioners are distributed on the surface of the ground, these can be carried off to rivers and contaminate them. Also, since they favor the development of parasite plants, hand labor is required to eliminate the latter.
In addition, because of its design, hydraulic equipment for surface watering by spray or drip is very expensive and delicate, and requires maintenance labor to eliminate the obstructions in tubes and drips because of the mould which develops in them, or other kinds of blockage. Also the regulation and control of flow rate of the drip equipment, and of pressures in the pipes and of the moistness of the ground, proves difficult and on some occasions impossible.
The system of irrigation by drip involves a considerable expenditure for the drippers used, the adaptation of the distribution pipes for a specific diameter for the use of such drippers, the need for calculations which take into account the roughness of the pipes, the pressure losses due to friction, the need for pipe appropriate to the topography of the ground, and the total hydraulic supply available.
Since excessive surface moisture favors the growth of parasite plants, infestations and insects and diseases of fungus origin, it becomes necessary to use pesticides derived from mercury, lead, copper, and other compounds and applied as herbicides, insecticides and fungicides, all of which causes contamination and ecological harm.